Over the past decade it has been well established that lost vestibular hair cells regenerate and are re-innervated. Although some information on vestibular responses during regeneration has been obtained, much remains to be learned regarding the functional recovery of compensatory neuromotor behaviors and their underlying neural mechanisms. We have recently developed a method for administration of streptomycin that results in complete hair cell loss and afferent denervation of the vestibular organs in adult pigeons at a discrete point in time. We have used the method to identify three separate stages of vestibular regeneration, where different morphological characteristics of hair cell distribution and afferent innervation were observed. We now propose to use the method to study the regenerative development of vestibular function. Our investigations will focus upon the recovery of afferents, central vestibulospinal neurons and gaze behavior during regeneration. The working conceptual framework is that a specific progression in vestibular neuromotor behaviors and the neuronal physiological responses that comprise them will occur during regeneration, as correlated to the three morphological stages of peripheral development. Both behavioral and physiological studies in alert pigeons will be used to test specific hypotheses derived from our conceptual framework. First, we will characterize the development of vestibular afferent responses during regeneration. The spatial tuning and response dynamics of afferents will be examined longitudinally during re-innervation of the vestibular receptors. Second, we will characterize the development of central vestibulospinal neuronal responses during regeneration. Third, we will characterize the compensatory eye and gaze responses in head free birds during regeneration. Increasing our fundamental understanding of the processes underlying regeneration recovery is essential before more effective treatments of vestibular system disorders can be realized. [unreadable] [unreadable]